Page 330 - Theory and Problems of BEGINNING CHEMISTRY

GLOSSARY 319

k Boltzmann constant: k = R/N = 1.38 × 10 −23 J/(molecule·K).

K a acid ionization constant.
K b base ionization constant.
K i acid or base ionization constant.
K w ionization constant for the autoionization of water.

kelvin the unit of the Kelvin temperature scale.
Kelvin temperature scale a temperature scale with its 0 at the lowest theoretically possible temperature
◦
(0 K =−273 C) and with temperature differences the same as those on the Celsius scale.
ketone an organic compound of the type RCOR .
kilo prefix meaning 1000.
kilogram the legal standard of mass in the United States; 1000 g.
1 2 1 2
kinetic energy energy of motion, as in a 10-ton truck going 50 mi/h: KE = mv = (10 ton)(50 mi/h)
2 2
(where m is mass and v is velocity).
kinetic molecular theory a theory that explains the properties of gases in terms of the actions of their molecules.

law an accepted generalization of observable facts and experiments.
law of conservation of energy energy cannot be created or destroyed.
law of conservation of mass mass is neither created nor destroyed during any process.

law of conservation of matter matter is neither created nor destroyed during any ordinary chemical reaction.
This law differs from the law of conservation of mass because rest mass can be converted into energy (which has
its own mass associated with it). Some matter is converted to energy in nuclear reactions.
law of definite proportions all samples of a given compound, no matter what their source, have the same
percentage of each of the elements.
law of multiple proportions in two compounds of the same elements, for a given mass of one element, the
two masses of each other element are in a ratio of small whole numbers.

lead storage cell a cell composed of Pb/PbSO 4 and PbO 2 /PbSO 4 electrodes in an H 2 SO 4 electrolyte.
Le Chˆ atelier’s principle if a stress is applied to a system at equilibrium, the equilibrium will shift in a tendency
to reduce the stress.
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light a form of energy. Light has both wave and particle properties, with a speed in vacuum of 3.00 × 10 m/s.
limiting quantity the reagent that will be used up before all the other reagent(s); the substance that will be
used up first in a given chemical reaction, causing the reaction to stop.
line formula a formula for an organic compound written on one line, in which bonded groups of atoms are
written together, for example, CH 3 CHClCH 3 .
liter the fundamental unit of volume of the classical metric system (about 6% greater than a U.S. quart).
(The cubic meter is the fundamental unit of volume in SI.)
ln key the key on the calculator that takes the natural logarithm of the number in the display.
log key the key on the calculator that takes the base 10 logarithm of the number in the display.

m (1) symbol for mass. (2) symbol for meter. (3) symbol for milli. (4) symbol for molal (unit of molality).
M symbol for molar, the unit of molarity.